1. Field of the Invention
The present invention relates to a rotary electric machine.
2. Discussion of the Background
Conventionally, a rotary electric machine has been known, in which permanent magnets are embedded in proximity to an outer circumferential portion of a rotor core (for example, refer to Japanese Unexamined Patent Publication No. 2003-47185).
In the rotary electric machine in the above patent document, a plurality of permanent magnets are embedded at an equal interval along a circumferential direction in proximity to the outer circumferential portion of the rotor core. Moreover, in the rotary electric machine in the above patent document, a stator core is provided so as to face to the rotor core in a radial direction, and in addition, windings are provided on the stator core. Then, the rotary electric machine is configured so that the rotor core rotates by magnetic fields generated from the windings and magnetic fields of the permanent magnets. Meanwhile, in the rotary electric machine of the above patent document, magnetization of end portions of the permanent magnets may be locally demagnetized irreversibly by an armature reaction ampere turn generated from the windings (that is, a magnetomotive force generated from the windings).
In another conventional rotary electric machine different from one in the above patent document, in order to reduce the irreversible demagnetization, a structure has been proposed, in which gaps are provided in portions of the rotor core on an outer circumference side of the permanent magnets.